Microscope

ABSTRACT

In a microscope, an optical system that includes a zoom lens unit having a straight optical axis is located under a stage portion that carries a sample A thereon. An optical image of the sample A is projected on an image-pickup element via the optical system, and is converted into a picture signal by means of the image-pickup element. The picture signal is delivered to the outside through an external terminal area.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2001-223480, filed Jul.24, 2001, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a microscope, and moreparticularly, to a microscope for converting an observed image of aspecimen, such as cellular tissue or a microorganism, into a picturesignal to be observed.

[0004] 2. Description of the Related Art

[0005] Computers are utilized in the field of education nowadays.Computerized education is expected to cover various courses of studythat utilize actual computers, as well as simple computer training.

[0006] In science education, for example, cellular tissue,microorganisms, etc. are directly observed with use of microscopes, andbesides, their observed images are supposed to be converted into picturesignals, which are to be observed on computers.

[0007] A conventional microscope that can generate those picture signalsis described in Jpn. Pat. Appln. KOKAI Publication No. 10-333055. Inthis microscope, a lens unit is located next to a specimen stageportion, and a CCD unit is situated on a bent optical path that extendsfrom the lens unit. In acquiring a picture signal, a specimen or sampleis placed on the specimen stage portion, and the stage portion isrotated to adjust the focus. Thereafter, an optical image of thespecimen is formed by means of the lens unit. The optical image formedin this manner is guided through the bent optical path to a CCDimage-pickup element of the CCD unit and converted into electricinformation, whereupon a picture signal is generated.

[0008] In the microscope described above, however, the optical imagethat is fetched by means of the lens unit is guided to the CCDimage-pickup element through the bent optical path. Therefore, themicroscope requires use of a lot of essential optical parts, so that itsconstruction is complicated and its optical performance is not veryhigh.

[0009] According to this conventional microscope, moreover, the focus isadjusted by rotating the specimen stage portion, so that the directionand position of the specimen on the stage portion inevitably shiftsduring the focus adjustment. Accordingly, its imaging range or pictureframe is unstable, so that the microscope is not easy to handle. It isvery hard for this microscope, in particular, to acquire picture data ofspecimens or sample that have directional shapes, among other specimensor sample including cellular tissue and microorganisms that are observedin educational scenes.

[0010] As described above, the conventional microscope has a slimoptical structure such that the optical image is guided to the CCDimage-pickup element through the bent optical path. Thus, the opticalpath is so complicated that the optical performance of the microscope ispoor.

BRIEF SUMMARY OF THE INVENTION

[0011] According to an aspect of the invention, there is provided amicroscope for observing a sample to output an electrical imageinformation relating to an image of the sample, comprising:

[0012] a stage portion configured to permit the sample to be mounted;

[0013] an image-pickup element, on which an optical image of the sampleis formed, configure to convert the optical image into the electricimage information,

[0014] an optical system, having the optical axis extending in astraight line between the stage portion and the image-pickup element,configured to guide the optical image of the sample to the image-pickupelement;

[0015] a light source unit including one light source configured to emitan illumination light beam for illuminating the sample and a mechanismconfigured to alternatively locate the light source in any of first,second, and third irradiative positions for transmissive illumination,incident illumination, and oblique illumination, thereby selecting oneof the transmissive illumination, incident illumination, and obliqueillumination.

[0016] According to an another aspect of the invention, there isprovided a microscope for observing a sample to output an electricalimage information relating to an image of the sample, comprising:

[0017] a stage portion configured to permit the sample to be mounted;

[0018] an image-pickup element, on which an optical image of the sampleis formed, configured to convert the optical image into the electricimage information,

[0019] an optical system, having the optical axis extending in astraight line between the stage portion and the image-pickup element,configured to guide the optical image of the sample to the image-pickupelement;

[0020] an optical lens barrel portion, the image-pickup element and theoptical system being arranged the optical lens barrel portion; and

[0021] a stage moving mechanism configured to support the stage portionon the optical lens barrel portion and move the stage within a planesubstantially perpendicular to the optical axis.

[0022] According to an another aspect of the invention, there isprovided a microscope for observing a sample to output an electricalimage information relating to an image of the sample, comprising:

[0023] a stage portion configured to permit the sample to be mounted;

[0024] an optical system, located under the stage portion and includinga zoom lens unit, configured to form the optical image of the sample;

[0025] an image-pickup element, which is arranged in the image formingposition of the optical system for the sample and on which the opticalimage is formed, configured to convert the optical image into theelectric image information,

[0026] an external output portion configured to convert the electricimage information generated from the image-pickup element into a picturesignal and delivering the signal to the outside of the microscope;

[0027] a base portion configured to hold the image-pickup element andthe external output portion;

[0028] a support structure configured to support the stage portion onthe base portion and also support the optical system;

[0029] a zoom control portion, located between the base portion and thestage portion, configured to move the zoom lens unit along the opticalaxis; and

[0030] a focus adjusting mechanism, supported under the stage portion bymeans of the support structure, configured to focus the optical systemon the sample.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0031] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0032]FIG. 1 is a perspective view schematically showing the externalappearance of a microscope according to an embodiment of the invention;

[0033]FIG. 2 is a schematic sectional view taken along the optical axisof the microscope of FIG. 1;

[0034]FIG. 3 is a cutaway plan view schematically showing a part of astage plate in order to illustrate the construction of the stage plate;

[0035]FIGS. 4A and 4B are perspective views schematically showing lensframes of a zoom lens unit shown in FIG. 1;

[0036]FIG. 5 is a development showing cam grooves formed on a turn ringin order to urge the lens frames shown in FIGS. 4A and 4B to move in thedirection of the optical axis;

[0037]FIG. 6 is a perspective view schematically showing a mode of useof the microscope shown in FIG. 1;

[0038]FIG. 7 is a partial sectional view schematically showing a part ofa microscope according to another embodiment of the invention;

[0039]FIG. 8 is a sectional view schematically showing a microscopeaccording to still another embodiment of the invention;

[0040]FIG. 9 is a sectional view schematically showing a microscopeaccording to a further embodiment of the invention;

[0041]FIG. 10 is a sectional view schematically showing the microscopeof FIG. 9 and illustrating the way a lighting system of the microscopeis used;

[0042]FIG. 11 is an enlarged plan view schematically showing a part ofthe microscope shown in FIG. 9; and

[0043]FIG. 12 is a partial sectional view schematically showing a partof a microscope shown in FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

[0044] A microscope according to an embodiment of the present inventionwill now be described in detail with reference to the accompanyingdrawings.

[0045]FIGS. 1 and 2 show the microscope according to the embodiment ofthe invention. FIG. 1 shows the external appearance of the microscope,and FIG. 2 shows a profile along the optical axis of the microscope.

[0046] As shown in FIG. 1, the microscope is in the form of a cylinderhaving a base portion 6 at the bottom and a stage portion 2 at the top.For example, the microscope is 187 mm high, and the base portion has anoutside diameter of 124 to 150 mm.

[0047] As shown in FIG. 2, the microscope comprises the stage portion 2that carries a sample A thereon, a zoom lens unit 3 as an optical systemcapable of focusing and changing the magnification of an optical imageof the sample A on the stage portion 2, and an image-pickup portion 4that includes an image-pickup element for detecting the optical imageenlarged by means of the zoom lens unit 3. All these portions aremounted on the base portion 6 so as to their respective optical axes aresubstantially on a straight line. The optical image is applied theimage-pickup portion 4 through the zoom lens unit 3 and the image-pickupportion 4 converts the input optical image into electric imageinformation and processes it to generate a picture signal. This picturesignal is externally delivered to an external apparatus, such as apersonal computer 20, through an external terminal unit 5 such as auniversal serial bus, which is so called USB. Thereupon, a picture of anobject of observation is displayed on a display device 30 which isconnected to the personal computer 20.

[0048] The stage portion 2 is provided with a stage plate 201 that hasan opening 201 a near its optical axis. As shown in FIG. 3, a pair ofcontrol knobs 203 and 204 are screwed into the outer peripheral surfaceof the stage plate 201 for sliding motion in a direction substantiallyperpendicular to the optical axis. They are spaced at about 90° inrespect to the optical axis of the microscope. A plunger 205 is opposedto the control knobs 203 and 204 so as to be slidable in the samedirection. The plunger 205 is pressed in a direction perpendicular tothe optical axis by means of a spring 205 a and a stopper screw 205 b.

[0049] The control knobs 203 and 204 and the plunger 205 have sphericalor rounded distal ends, respectively. A stage support base 202 isprovided with a ring section having an outer peripheral surface on whichrecesses 202 b are formed. Each of the recesses 202 b has a inclinedface for receiving a corresponding one of the distal ends of the controlknobs 203 and 204 and the plunger 205. The spherical distal ends of thecontrol knobs 203 and 204 and the plunger 205 are contacted to the faceof the recesses 202 b formed on the outer peripheral surface of thestage support base 202. Each of the recesses 202 b is formed as acircular corn space and has a part of the face inclined to the specimenor sample A and extended as to face the specimen or sample A. As thedistal ends of the control knobs 203 and 204 is pressed to the inclinedface of the recess 202 b, a pressing force is produced between the facesand the distal ends of the control knobs 203 and 204 and the pressingforce is applied to the control knobs 203 and 204 in a direction awayfrom the specimen A.

[0050] Thus, the pressing force is applied to not only the control knobs203 and 204 but also the stage plate 201 in the direction of the stagesupport base 202, i.e., in the direction away from the specimen A.Accordingly, a lower surface 201 b of the stage plate 201 is pressedagainst an upper surface 202 a of the stage support base 202, wherebythe stage plate 201 can be mounted on the stage support base 202 withoutplay. When the control knobs 203 and 204 are rotated, so-called framingis executed such that they control the stage plate 201 for an orthogonalmovement in the horizontal direction and a rotational movement inconjunction with the plunger 205, thereby setting the stage plate 201 ina desired position on the stage support base 202.

[0051] The stage support base 202 may have an inclined outer peripheralsurface, instead of the recess 202 b formed on the outer peripheralsurface of a stage support base 202. The respective distal ends of thecontrol knobs 203 and 204 and the plunger 205 are so contacted andengaged on the inclined outer peripheral surface as to apply a contactpressure to the inclined outer peripheral surface in a direction awayfrom the stage plate 201 and urge the stage plate 201 to be contacted onthe stage support base 202.

[0052] The zoom lens unit 3 includes first, second, third, fourth,lenses 301, 302, 303, 304 and 305, which are arranged so that theiroptical axis B extends in a straight line. The first lens 301 is formedof an auxiliary lens called a conversion lens, and is fixed to a lensframe 306 by means of a ring spring 307. The lens frame 306 is slidablyfitted in a fitting portion 202 c that is situated near the optical axisof the stage support base 202.

[0053] Further, a groove 306 a is formed on the outer periphery of thelens frame 306. An eccentric pin 206 a of a focusing handle 206 that isrotatably attached to a side hole 202 d of the stage support base 202 isfitted in the groove 306 a.

[0054] In addition, the eccentric pin 206 a is eccentrically positionedfrom the rotating center of the focusing handle 206. A stopper pin fixedin the support base 202 is engaged with the focusing handle 206 so thatthe handle 206 is prevented from being dropped out from the supportbase. Thus, the handle 206 is rotatably held in the support base 202 bymeans of a spring washer 208 and washer 209 which apply a moderate forceto the handle 206.

[0055] As the handle 206 is so operated as to rotate, the eccentric pin206 a is rotated around the center of the handle 206 with a radius ofthe eccentric distance between the centers of the handle and theeccentric pin 206 a. Accordingly, the first lens 301 can be moved in thedirection of its optical axis to bring the sample A into focus.

[0056] The second lens 302 is fixed in the fitting portion 202 c of thestage support base 202 by means of the ring spring 308. The third lens303 is fixedly bonded o a lens frame 309 that has a fitting hole 309 aand a fitting slit 309 b shown in FIG. 4A. The fitting hole 309 a andthe fitting slit 309 b of the lens frame 309 are fitted individually ontwo support posts 602 for use as support members for axial movementalong the optical axis. Further, the fourth lens 304 is fixedly bondedon a lens frame 310 that has a fitting hole 310 a and a fitting slit 310b shown in FIG. 4B. The fitting hole 310 a and the fitting slit 310 b ofthe lens frame 310, like those of the lens frame 309, are fittedindividually on the two support posts 602 for axial movement along theoptical axis.

[0057] The two support posts 602 are fixed in a manner such that theyare arranged between the stage support base 202 and a base 601 of thebase portion 6. The support posts 602 are surrounded by a turn ring 603that has cam grooves 603 a and 603 b in its inner wall, as shown in FIG.5 as described later. As shown in FIG. 2, the upper and lower end facesof the turn ring 603 is held between the stage support base 202 and thebase 601 with narrow gaps between them. The top and bottom portions ofthe turn ring 603 are rotatably fitted on cylindrical protrusions of thestage support base 202 and the base 601, respectively.

[0058] A cam follower 309 c on the lens frame 309 and a cam follower 310c on the lens frame 310 are fitted in the cam grooves 603 a and 603 b ofthe turn ring 603, respectively. As shown in the development of FIG. 5,for example, the cam grooves 603 a and 603 b are formed having a desiredshape such that the image of the sample A can be enlarged and reduced insize by means of the third and fourth lenses 303 and 304 as it is formedon the respective focal points of the lenses.

[0059] Thus, when the turn ring 603 is so operated as to rotate, the camfollowers 309 c and 310 c are guided on the cam grooves 603 a and 603 b,respectively, to move the third an fourth lenses 303 and 304 (indicatedby two-dot chain lines in FIG. 2), thereby enlarging and reducing theoptical image of the sample A.

[0060] The fifth lens 305 is fixedly fitted in the base 601 by means ofa ring spring 604.

[0061] Further, the image-pickup portion 4 includes an image-pickupelement 401, which receives the optical image of the sample A enlargedby means of the zoom lens unit 3 and converts it into electricinformation, and a circuit board 402 for holding the image-pickupelement 401. The circuit board 402 is fixed on the base 601 of the baseportion 6 in a manner such that the image-sensing surface of theimage-pickup element 401 that is formed integrally with the board 402 isin line with the optical focal point (image forming point) of the zoomlens unit 3.

[0062] Furthermore, the external terminal area 5 includes a processor501 formed integrally on the circuit board 402 and a terminal 503 suchas a USB to be connected with the personal computer 20. The processor501 processes the electric information from the image-pickup element 401and converts it into a picture signal that can be outputted externally.The processor 501 and the terminal 503 are connected electrically toeach other by means of a lead wire 502, and are configured to be able tooutput the picture signal externally or be supplied with power from thepersonal computer. Thus, the image-pickup portion 4 is supplied withpower from the personal computer that is connected to the externalterminal area 5 as its drive is controlled. In consequence, the numberof parts used in the microscope can be reduced, so that the microscopecan be simplified in construction and reduced in size.

[0063] In observing the sample A in this arrangement, the personalcomputer is first connected to the external terminal area 5. If this isdone, the image-pickup portion 4 is supplied with power from thepersonal computer, and the turn ring 603 is operated to rotate.Thereupon, the cam followers 309 c and 310 c of the lens frames 309 and310 of the third and fourth lenses 303 and 304 are guided by the grooves603 a and 603 b of the turn ring 603, as mentioned before, so that themovement of the zoom lens unit 3 in the direction of the optical axis isadjusted, and the magnification of the formed optical image is settled.

[0064] As this is done, the control knobs 203 and 204 are rotated toadjust the movement of the stage plate 201 and frame the sample A in adesired position. At the same time, the rotation of the focusing handle206 is adjusted to regulate the movement of the first lens 301 in thedirection of the optical axis, thereby bringing the sample A into focus.

[0065] The optical image of the sample A placed on the stage plate 201is enlarged by means of the zoom lens unit 3, and is formed andconverted into electric information by means of the image-pickup element401 of the image-pickup portion 4. The electric information is processedto generate a picture signal. This picture signal is delivered to thepersonal computer 20 through the external terminal area 5. As this isdone, the image-pickup portion 4 is supplied with power from thepersonal computer through the external terminal area 5, as mentionedbefore, whereby its operation is controlled.

[0066] According to this arrangement, the image-pickup element 401 isopposed straight to the underside of the stage portion 2 across the zoomlens unit 3 that has a straight optical axis. The picture signal isgenerated from the electric information converted by means of theimage-pickup element 401 and outputted externally. Accordingly, theoptical path is simplified, and miniaturization and simplification ofconstruction can be realized without failing to maintain high-efficiencyoptical performance. Thus, the ease of handling of the microscope,including its portability, can be improved. According to thisarrangement, moreover, a picture signal for an optical image with aseamless magnification can be acquired with ease.

[0067] According to this arrangement, furthermore, the microscope is theso-called inverted microscope in which the zoom lens unit 3 is locatedon the backside of the stage plate 201 of the stage portion 2 on top ofwhich the sample A is placed. Therefore, the sample A to be observed isnot limited in size, and may be any substance that can be placed on thestage plate 201 of the stage portion 2. Thus, a wide variety of objectscan be observed. As shown in FIG. 6, for example, a user 100 can observethe surface of a bulky object, such as the bark of a tree 100, in amanner such that he/she holds the turn ring 603 and applies the stageplate 201 of the stage portion 2 to the tree.

[0068] According to this arrangement, moreover, the sample A can bebrought into focus by adjusting the movement of the first lens 301 ofthe zoom lens unit 3 with the stage plate 201 fixed. Thus, high-accuracyfocus adjustment can be effected by simply rotating the focusing handle206, and the sample A on the stage plate 201 can be framed by onlyrotating the control knobs 203 and 204 to adjust the movement of thestage plate 201 on a flat surface.

[0069] According to the embodiment described above, furthermore, thefirst lens 301 of the zoom lens unit 3 is provided as focus adjustingmechanism for movement in the direction of the optical axis.Alternatively, however, the focus adjusting mechanism may be arranged inthe manners shown in FIGS. 7 and 8. In FIGS. 1 to 5 and FIGS. 7 and 8,like numerals are used to designate like portions, and a detaileddescription of those portions is omitted.

[0070] In the arrangement shown in FIG. 7, the fifth lens 305 is locatedfor movement in the direction of the optical axis with respect to thebase 601, and its movement in the direction of the optical axis can beregulated for focus adjustment. More specifically, the fifth lens 305 isattached to a lens frame 305 a by means of the ring spring 604, and thelens frame is mounted on the base 601 for movement in the direction ofthe optical axis. A driven groove 305 b is formed around the lens frame305 a, and the eccentric pin 206 a on the focusing handle 206 can beinserted into the groove 305 b. The handle 206 is rotatably mounted onthe base 601 by means of the stopper pin 207, spring washer 208, andwasher 209. As the handle 206 is rotated, the lens frame 305 a of thefifth lens 305 can be moved in the direction of the optical axis bymeans of the eccentric pin 206 a to adjust the focus of the zoom lensunit 3.

[0071] According to this arrangement, the focus can be adjusted near thebase portion 6, so that the user 100 can operate the microscope withhis/her hand on a desk. Thus, stable adjustment operation can berealized.

[0072] Focus adjusting mechanism capable of adjusting the focus bymoving the fifth lens 305 in the direction of the optical axis can becombined with the foregoing focus adjusting mechanism that uses thefirst lens 301. By doing this, the range of focus adjustment can bewidened, and the mode of observation can be diversified. If the firstand fifth lenses 301 and 305 are differentiated in optical power, inthis case, the focusing effect of the first lens 301 compared with itsmovement can be made different from the focusing effect of the fifthlens 305. Thus, rough- or fine-movement focusing operation can becarried out by operating these lenses separately.

[0073] In the arrangement shown in FIG. 8, moreover, the overall lengthof the turn ring 603 is made shorter than that of each support post 602so that there are gaps a and b between the ring 603 and the base 601 andbetween the ring 603 and the stage support base 202, respectively.According to this arrangement, the turn ring 603 doubles as a controlportion for the enlargement and reduction of the image of the sample Aand as a control portion for bringing the sample A into focus.Accordingly, the operations for focusing and for the enlargement andreduction of the sample image can be carried out by manipulating onlyone part. Thus, the handling operation can be simplified, and the numberof essential parts can be reduced.

[0074] According to this embodiment, moreover, the turn ring 603 can bemoved in the direction of the optical axis by means of an eccentric pinor any other control means without being directly operated, as in thecase of the operation for moving the first lens 301 of the foregoingembodiment. By doing this, defocus during the operation for theenlargement and reduction of the sample image can be reduced, andadditional effects can be expected.

[0075] The present invention is not limited to the embodiments describedabove. A light source unit 8 may be provided on the stage base portion 2shown in FIGS. 9 to 11, which corresponds to the stage base portion 2shown in FIG. 2. In FIGS. 1 to 5 and FIGS. 9 to 11, like numerals areused to designate like portions, and a detailed description of thoseportions is omitted.

[0076] The light source unit 8 includes a light source 801 and a powersupply controller 802 such as a variable resistor, for power supplycontrol, which are mounted on a base plate 804. The controller 802 isconnected electrically to the image-pickup portion 4 or circuit board402 by means of a cable 803.

[0077] A cylindrical part 806 is located around the light source 801. Acondenser lens 807 is attached to the cylindrical part 806 by means of aring spring 805. The lens 807 is used to focus light from the lightsource 801 on the sample A that is placed on the stage portion 2. Thebase plate 804 and the cylindrical part 806 are fixedly supported on oneend portion of an arm 809. The other end portion of the arm 809 isattached to a stage support base 210 by means of a fixing knob 808 sothat its angle around the axis of the knob 808 is adjustable. The baseplate 804 and the cylindrical part 806 that are supported by means ofthe arm 809 are enveloped in a sheathing cover 810, which is indicatedby two-dot chain line in FIG. 9, for example. A part of the cylindricalpart 806 projects outside the sheathing cover 810 in order to irradiatethe stage plate 201 with the light from the condenser lens 807.

[0078] A hole 210 a is formed in the side face of the stage support base210. Illumination light from the light source unit 8 is applied to thesample A through the hole 210 a from under the stage plate 201 as thearm 809 is rocked around its axis.

[0079] If the personal computer 20 shown in FIG. 2 is connected to theterminal 503 of the external terminal area 5 in this arrangement,electric power that is supplied from the personal computer is suppliedto the light source unit 8 through the image-pickup portion 4, whereuponthe sample A on the stage plate 201 is illuminated by transmission. Asthis is done, the supplied power can be adjusted by operating thecontroller 802, so that an image with steadier brightness and color canbe obtained.

[0080] If the arm 809 is tilted with the fixing knob 808 loosened,moreover, oblique transmissive illumination can be effected by means ofthe light source unit 8. Incident illumination or oblique incidentillumination through the hole 210 a of the stage support base 210 can berealized by adjusting the tilt angle of the light source unit 8 in amanner such that the source unit 8 is tilted so as to face the hole 210a, as indicated by two-dot chain line in FIG. 10, for example.

[0081] According to this embodiment, the light source unit 8 can applysteadier illumination light to the sample A, so that a bright,high-resolution image can be obtained, and high-accuracy observation canbe facilitated. Further, the observation mode can be switched betweentransmissive-illumination observation, incident-illuminationobservation, and oblique-illumination observation by simply rocking thearm 809 around its axis. Thus, various observation methods can berealized with ease. According to this arrangement, furthermore, electricpower from the personal computer 20 is supplied to the light source unit8 through the circuit board 402, so that the number of essential partscan be reduced, and therefore, the microscope can be miniaturized.

[0082] The light source unit 8 can be easily adjusted to differentillumination modes by attaching the arm 809 to the stage support base210 in the manner showing 11, for example. More specifically, the stagesupport base 210 is provided with a protuberance 210 c that has anangled reference surface 210 b for arm attachment. The arm 809 isprovided with two surfaces 809 a and 809 b that are inclined at givenangles, corresponding to the reference surface 210 b of the protuberance210 c.

[0083] In this arrangement, the light source unit 8 can be accuratelylocated in a predetermined position suited for transmissive illuminationby fixing the arm 809 by means of the fixing knob 808 with the surface809 a of the arm 809 held against the reference surface 210 b of theprotuberance 210 c of the stage support base 210. Thus, transmissiveillumination is executed (see FIG. 10). Then, the fixing knob 808 isloosened, and the arm 809 is lifted above the protuberance 210 c androtated. In this state, the arm 809 is fixed by means of the fixing knob808 with the surface 809 b held against the reference surface 210 b ofthe protuberance 210 c this time. The light source unit 8 is positionedfor incident illumination, facing the hole 210 a of the stage supportbase 210, as indicated by two-dot chain line in FIG. 10, and incidentillumination is executed.

[0084] Thus, illumination in a predetermined position can be easilyrepeated by using the single light source unit 8. For example, a desiredstate of illumination, such as a state with the best optical performanceor a bright state, can be easily reproduced, so that the ease ofhandling of the microscope can be improved.

[0085] The fixing knob 808 is rotatably mounted on the protuberance 210c of the stage support base 210 with its central axis C or axis ofrotation deviated from the optical axis B for a distance X correspondingto the hole 210 a. Thus, by only variably setting the distance X of thelight source unit 8, ranges of illumination for a light beam D fortransmissive observation and a light beam E for incident observation canbe set with ease, as shown in FIG. 10, for example.

[0086] In each of the embodiments described above, the stage plate 201that constitutes the stage portion 2 is mounted on the stage supportbase 202 (210) by means of the control knobs 203 and 204 and the plunger205 in a manner such that it can move and rotate on a plane substantialperpendicular to the optical axis of. Alternatively, however, the stageportion may be of a so-called grinding-stage structure such that thestage plate 201 is mounted on the stage support base 202 (210) with useof pasty oil, such as grease, for movement and rotation on a planesubstantially perpendicular to the optical axis. According to thisarrangement, the stage plate 201 can be framed more easily.

[0087] In the embodiment described above, the microscope has theconfiguration wherein the stage plate 201 constituting the stage portion2 is mounted on the stage support base 202 by means of the control knobs203, 204 and the plunger 205 in such a manner that the stage plate 201is controlled to be moved and rotated on the plane perpendicular to theoptical axis of the optical system. However, in this invention, it isnot limited to that configuration and a modified configuration can beapplied to the stage structure. In an example of the modifiedconfiguration, the stage portion has a gliding stage structure in whichthe control knobs 203, 204 and the plunger 205 are removed from theconfiguration shown in FIG. 2, and a pasty oil such as a grease isapplied between the stage plate 201 and the stage base 202 to allow thestage plate to be moved and rotated on the plane perpendicular to theoptical axis of the optical system.

[0088] This stage configuration can realize a easy to handle the stageplate 201 and a simple operation of the framing with utilizing the stageplate 201.

[0089] According to the embodiment described above, moreover, the twosupport posts 602 are used as support members to couple the stagesupport base 202 to the base 601. Alternatively, however, three or moresupport posts 602 may be used to couple the stage support base 202 (210)and the base 601.

[0090] According to the embodiment described above, furthermore, thecontroller 802, i.e., the variable resistor, for controlling andadjusting the electrical power supply is mounted on the light source801. However, it is not limited that the controller 802 is mounted onthe light source. Alternatively, the controller 802 may be mounted onthe circuit board 402, which is provided in the base 601 of the baseportion 6, and an operating part 802 b of the controller 802 is soprovided as to project from the base 601 along the turn ring 603. Inthis arrangement, it is easy to handle the magnification adjustment ofthe zoom lenses and the light intensity control of operating the powersupply adjustment, because the operating part of the controller 802 islocated in the vicinity of the turn ring 603.

[0091] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A microscope for observing a sample to output anelectrical image information relating to an image of the sample,comprising: a stage portion configured to permit the sample to bemounted; an image-pickup element, on which an optical image of thesample is formed, configure to convert the optical image into theelectric image information, an optical system, having the optical axisextending in a straight line between the stage portion and theimage-pickup element, configured to guide the optical image of thesample to the image-pickup element; a light source unit including onelight source configured to emit an illumination light beam forilluminating the sample and a mechanism configured to alternativelylocate the light source in any of first, second, and third irradiativepositions for transmissive illumination, incident illumination, andoblique illumination, thereby selecting one of the transmissiveillumination, incident illumination, and oblique illumination.
 2. Amicroscope according to claim 1, wherein the optical system includes azoom lens unit, and the microscope further comprises a base portion, aplurality of support members supporting the stage portion on the baseportion, a lens frame supporting the zoom lens unit on the supportmembers, and a lens frame moving mechanism configured to move the lensframe along the optical axis.
 3. A microscope according to claim 1,which further comprises a hollow rotating cylinder portion rotatablyattached to the base portion and the stage portion, and wherein theoptical system is received in the rotating cylinder portion, and thelens frame moving mechanism is actuated to move the lens frame along theoptical axis as the rotating cylinder portion is rotated.
 4. Amicroscope according to claim 1, wherein the optical system includes alens for adjusting the focus of the optical system, and the microscopefurther comprises a fine-movement mechanism configured to finely movethe focus adjusting lens in the direction of the optical axis, therebyfocusing the optical system on the sample.
 5. A microscope according toclaim 1, wherein the light source unit includes an arm member configuredto support the light source, which is attached to the stage portion foradjustable rotation, and the light source is alternatively located inone of the first, second, and third irradiative position as the armmember is rotated.
 6. A microscope for observing a sample to output anelectrical image information relating to an image of the sample,comprising: a stage portion configured to permit the sample to bemounted; an image-pickup element, on which an optical image of thesample is formed, configured to convert the optical image into theelectric image information, an optical system, having the optical axisextending in a straight line between the stage portion and theimage-pickup element, configured to guide the optical image of thesample to the image-pickup element; an optical lens barrel portion, theimage-pickup element and the optical system being arranged the opticallens barrel portion; and a stage moving mechanism configured to supportthe stage portion on the optical lens barrel portion and move the stagewithin a plane perpendicular to the optical axis of the optical system.7. A microscope according to claim 6, wherein the optical systemincludes a zoom lens unit, and the microscope further comprises a baseportion, a plurality of support members supporting the stage portion onthe base portion, a lens frame supporting the zoom lens unit on thesupport members, and a lens frame moving mechanism configured to movethe lens frame along the optical axis.
 8. A microscope according toclaim 6, which further comprises a hollow rotating cylinder portionrotatably attached to the base portion and the stage portion, andwherein the optical system is received in the rotating cylinder portion,and the lens frame moving mechanism is actuated to move the lens framealong the optical axis as the rotating cylinder portion is rotated.
 9. Amicroscope according to claim 6, wherein the optical system includes alens for adjusting the focus of the optical system, and which furthercomprises a fine-movement mechanism configured to finely move the focusadjusting lens in the direction of the optical axis, thereby focusingthe optical system on the sample.
 10. A microscope according to claim 6,which further comprises a light source unit having one light sourceconfigured to emit an illumination light beam for illuminating thesample and a mechanism configured to alternatively locate the lightsource in any of first, second, and third irradiative positions fortransmissive illumination, incident illumination, and obliqueillumination, thereby selecting one of the transmissive illumination,incident illumination, and oblique illumination.
 11. A microscopeaccording to claim 6, wherein the stage moving mechanism includes astage support base supporting the stage portion for movement and aregulating mechanism for regulating the movement of the stage portion onthe stage support base within a plane substantially perpendicular to theoptical axis.
 12. A microscope for observing a sample to output anelectrical image information relating to an image of the sample,comprising: a stage portion configured to permit the sample to bemounted; an optical system, located under the stage portion andincluding a zoom lens unit, configured to form the optical image of thesample; an image-pickup element, which is arranged in the image formingposition of the optical system for the sample and on which the opticalimage is formed, configured to convert the optical image into theelectric image information, an external output portion configured toconvert the electric image information generated from the image-pickupelement into a picture signal and delivering the signal to the outsideof the microscope; a base portion configured to hold the image-pickupelement and the external output portion; a support structure configuredto support the stage portion on the base portion and also support theoptical system; a zoom control portion, located between the base portionand the stage portion, configured to move the zoom lens unit along theoptical axis; and a focus adjusting mechanism, supported under the stageportion by means of the support structure, configured to focus theoptical system on the sample.
 13. A microscope according to claim 12,wherein the support structure includes a stage support base configuredto support the stage portion within a plane substantially perpendicularto the optical axis, which is provided with the focus adjustingmechanism configured to adjust a focus of the optical system, and asupporting portion configured to support the stage support base on thebase portion.
 14. A microscope according to claim 12, wherein thesupport structure includes a plurality of support members configured tosupport the stage portion on the base portion and a lens framesupporting the zoom lens unit on the support members, and which furthercomprises a lens frame moving mechanism configured to move the lensframe along the optical axis.
 15. A microscope according to claim 14,which further comprises a hollow rotating cylinder portion rotatablyattached to the base portion and the stage portion, and wherein theoptical system is located in the rotating cylinder portion, and the lensframe moving mechanism is actuated to move the lens frame along theoptical axis as the rotating cylinder portion is rotated.
 16. Amicroscope according to claim 13, which further comprises a light sourceunit having one light source configured to emit an illumination lightbeam for illuminating the sample, and a mechanism configured toalternatively locate the light source in any of first, second, and thirdirradiative positions for transmissive illumination, incidentillumination, and oblique illumination, thereby selecting one of thetransmissive illumination, incident illumination, and obliqueillumination, the light source unit including an arm member configuredto support the light source and attached to the stage support base foradjustable rotation, the light source being alternatively located in oneof the first, second, and third irradiative position as the arm memberis rotated.